This invention generally relates to automatic electrically powered door operators, and more particularly to an advance warning system for such operators which will alert persons in the vicinity of the door or the operator mechanism that operation of the door is eminent.
As the use of automatic electric door operators has increased in the past few years, so have the number of injuries caused by these devices. While they are not inherently unsafe, they are like many other machines and power tools in that they may be operated in an unsafe way. Of particular concern from a safety standpoint is the type of electric door operator which can be actuated from a location remote from the door with an electromagnetic or sonic transmitter such as a common garage door opener. One problem with these particular operators is that persons may and often do actuate them when they are not in a position to observe the doors. As a result, persons in the proximity of the door or the operator mechanism may be endangered.
Injuries and damages have also occurred when such doors have been actuated by spurious or "phantom" signals from passing aircraft, other sources of electromagnetic radiation, and even accidentally transmitted commands. In connection with such incidents, people have been struck by the doors, crushed under the doors or caught in the operator mechanisms. There have also been incidents wherein small children have been strangled by ropes attached to the doors for use in manual operation.
Presently known electric door operators do not include any means to provide advance warning to persons nearby that operation of the door is imminent. The only safety device commonly used with the operators is a door reversing mechanism which senses the amount of resistance to movement encountered by the door and reverses the motion of the door when the resistance reaches a certain predetermined level. These mechanisms are not adequate to prevent many of the above mentioned injuries or damages and will not necessarily prevent serious injuries to small children. Also, their effectiveness can be reduced or eliminated if they are not properly adjusted.
Accordingly, it is a principal object of this invention to provide for an advance warning system for automatic electric door operators which will warn persons in the proximity of the door or the operator mechanism that operation of the door is imminent. Another object of this invention is to provide an advance warning system which can be easily adapted to existing automatic electric door operators without significantly increasing their cost.
A further object of this invention is to provide an advance warning system for automatic electric door operators including a warning light and an audible signal which can be recognized and responded to even by a small child.